FFDSHOW is a DirectShow decoding filter for decompressing DivX, XviD, WMV, MPEG-1 and MPEG-2 movies. It uses libavcodec from ffmpeg project for video decompression, postprocessing code from mplayer to enhance visual quality of low bitrate movies, and is based on original DirectShow filter from XviD, which is GPL'ed educational implementation of MPEG4 encoder. Features:

fast video decompression using optimized MMX, SSE and 3DNow! code
support for different codecs: XviD, all DivX versions, MS WMV, MPEG-1 and - MPEG-2
image postprocessing for higher playback quality
automatic quality control: automatically reduces postprocessing level when CPU load is high
hue, saturation and luminance correction
experimental sharpening filter
noising (of course if you want it)
presets
completely free software: ffdshow is distributed under GPL
support for various subtitle formats

Download: FFDShow MPEG-4 Video Decoder 25-02-2004 [1 MB]